The study of the influence of drug abuse on immune function and the development of infection is a field with limited human data. Although the current epidemic of AIDS has focused attention on members of this high-risk group who are HTLV-III positive, much less attention has been given to the background risk of immune abnormalities and infections in those who are HTLV-III negative. The effect in infants of maternal drug abuse on immune function and the occurrence of infection is even less reported and understood. This study is a comprehensive evaluation of the immunologic and infectious effects on infants of maternal drug abuse. The hypotheses to be tested are that 1) maternal drug abuse during pregnancy puts the infants at increased risk of infection compared to infants of non-abusing mothers; 2) maternal drug abuse is associated with deficient immunologic function in the offspring; 3) the incidence of infections and/or immunologic dysfunction is increased in the presence of co-factors (lymphotropic virus infection, use of IV drugs, use of opiates and dysfunctional family dynamics). Drug abusing mothers and their infants will be enrolled from the Center for Chemical Dependence of the Northwestern University and the University of Illinois Hospital and Clinics while the control population will come from a local HMO. They will be studied at 3- 7 days of age and 2, 4, 7 and 12 months of age, and every six months thereafter. Sixty infants of mothers who abuse oral drugs, 80 who abuse IV drugs and 120 age-matched infants whose mothers do not abuse drugs will be enrolled. The data to be collected includes: 1) maternal drug, medical and social history: 2) infants medical history; 3) infants physical examination data; 4) serologic evidence of HTLV-III, CMV, EBV infection in mother and infant; 5) immunologic function including immunoglobin levels, tetanus antibody levels, blastogenic response to mitogens and antigen, natural killer activity and T-cell phenotype. The data analysis will include the effects of IV vs. oral drug abuse, narcotic vs. non-narcotic abuse and the influence of HTLV-III positivity.